One product photo, a whole campaign — a Nano Banana Pro field guide

Google's Nano Banana Pro — the Gemini 3 Pro image model — is genuinely good for brand work, but almost everything written about it is viral one-offs, not a method you can run twice and get the same brand back. So I wrote a field guide for it. Companion site · repo.

The whole guide collapses to one move: mint a single product master first — one file, the product from a few angles with its real label — then attach it to every image you generate afterward. The world changes, the product stays. That's what stops variation #47 from looking like a different brand than #1.

I also ran a fair tier bake-off — Pro vs 2 vs Lite, same prompt, same seed, master attached to all of them — instead of the usual test where each model invents its own label from scratch. Once there's a reference attached, all four hold the brand, and the difference collapses to render quality, speed and price. Nano Banana 2 came out the value pick: richest result at 2K for half of Pro's cost. And 'Lite' is misnamed — it's faster (~7s), but at $1/unit it isn't cheaper, so it's a sketchpad, not a volume play.

Everything in the guide was generated by a Claude skill that ships in the repo, so the images are reproducible rather than cherry-picked. The site runs beginner-to-advanced; the skill is the part I'd actually keep.